Investment Securities - Amortized cost and estimated fair value (Details) $ in Thousands	Sep. 30, 2020 USD ($)
Amortized Cost
Due within one year or less	$ 16,132
Due after one year through five years	26,821
Due after five years through ten years	145,310
Due after 10 years	293,075
Total investment securities available-for-sale	481,338
Fair Value
Due within one year or less	16,211
Due after one year through five years	27,459
Due after five years through ten years	150,121
Due after 10 years	301,623
Total investment securities available-for-sale	$ 495,414

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth fiscal year through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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